Field of the Invention
The invention relates in general to an image processing technology, and more particularly to a frame buffer for storing image data.
Description of the Related Art
With the thriving development of various kinds of digital electronic products, most current audiovisual multimedia data exists in a digital format. Digital files of audiovisual data are usually quite large, and the amount of data increases as the resolution gets higher. For example, in applications of video phone calls or digital televisions, the audiovisual data is usually transmitted by streaming via a wireless network. Due huge amounts of data, an issue of insufficient transmission bandwidth may occur. Thus, a transmitter first encodes the audiovisual data by digital audiovisual coding technologies before transmitting the audiovisual data. MPEG-4 and H.264 are some current common digital audiovisual coding technologies.
After a receiver receives encoded audiovisual data, a decoder decodes and restores the received data to the audiovisual data that the transmitter transmits. In many receivers, a double data rate synchronous dynamic random access memory (DDR DRAM) is used as a buffer for buffering the restored audiovisual data for the use of subsequent image processing.
Decoded audiovisual data includes multiple video frames stored in a frame buffer. Each video frame is defined to have multiple image blocks, and each image block serves as a unit by which the video frame is access for subsequent image processing. For example, the video frame in FIG. 1(A) includes an image block (0, 0) to an image block (M, N), with the size of the image blocks being constant.
However, the space of the frame buffer used is also large as a result of an extremely large amount of audiovisual data. On the other hand, when image processing is performed, in order to increase the speed of accessing the audiovisual data from the frame buffer, a memory having a larger bandwidth and also being more costly is required. Thus, the overall costs of the hardware system is increased.